Story at-a-glance -

Conventionally-grown
kale is frequently contaminated with high amounts of pesticides, making
it important to buy organic. Better yet, grow your own. Kale is easy to
grow and one of the most pest-resistant vegetables

Three
or four plants can supply enough greens each week for a family of four,
and the plants grow well in containers if you don’t have a backyard.
Many gardeners appreciate kale for their ornamental value as well

By Dr. MercolaKale1 — a well-recognized "superfood" — is rich in healthy fiber and antioxidants,
and is one of the best sources of vitamin A, which promotes eye and
skin health and may help strengthen your immune system, and vitamin K.
A 1-cup serving has almost as much vitamin C as an orange and as much
calcium as a cup of milk. It's also an excellent source of lutein and
zeaxanthin (which help protect against macular degeneration),
indole-3-carbinol (thought to protect against colon cancer by aiding DNA
repair), iron and chlorophyll.
One serving of kale also contains 2 grams of protein, 121 milligrams
(mg) of plant-based omega-3 fats, 92 mg of omega-6, and — like meat —
all nine essential amino acids needed to form proteins in your body,
plus nine nonessential ones for a total of 18. Studies suggest kale can
help lower total cholesterol and LDL cholesterol while raising HDLs, lowering your risk for heart disease. Kale has also been shown to provide "comprehensive support" for detoxification by regulating the process at the genetic level.2

Kale Is Simple to Grow and Provides Ornamental Beauty

Unfortunately, conventionally-grown kale is frequently contaminated with high amounts of pesticides,3 making it important to buy organic. Better yet, grow your own!
As little as three or four plants can supply enough greens each week
for a family of four, and the plants grow well in containers if you
don't have a backyard. Many gardeners appreciate kale for their
ornamental value as well. Growing your own will also give you better
control over soil conditions.

Are Concerns About Thallium Toxicity Valid?

Like many other
greens, kale tends to concentrate toxins present in the soil, and
thallium toxicity has been reported even in organically-grown kale.
Media warnings about "kale poisoning" erupted two years ago after
private experiments by molecular biologist Ernie Hubbard suggested
people were being exposed to dangerous levels of heavy metals from
plants like kale.
The story broke in the magazine Craftmanship Quarterly.4
Huffington Post was one of the few news sources trying to clarify the
media miscommunication that followed, noting the errors in journalism.5 Anna Almendrala wrote, in part:

"Hubbard, an unaffiliated scientist from Marin, California, who
works at an alternative health clinic, has been testing local kale and
soil and has arrived at the conclusion that the cruciferous vegetable's
ability to 'hyperaccumulate' the heavy metal thallium is posing a health
risk to his community.

Hubbard tested levels of thallium in vegetable samples and in the
urine of people from Marin … who have complained of things like
fatigue, brain fogginess and nausea. The symptoms are signs, he said,
that they may be experiencing low-level heavy metal poisoning.

These signs, however, are correlative, which means Hubbard
doesn't know for sure if crucifers have caused the symptoms or if
something else may be at play. But this hasn't stopped other outlets
from recommending that their readers cut back on certain vegetables …

[T]here's no reliable evidence to suggest you should kick your
kale to the curb, confirmed Shreela Sharma, a registered dietitian and
associate professor in the department of epidemiology, human genetics
and environmental sciences at the University of Texas Health Science
Center at Houston.

Hubbard acknowledged the limitations of his research to HuffPost,
and wrote in an email that he never intended for his preliminary
results to stand on their own, without corroboration, as a prescription
for the general public."

It's important to realize that nutrient and contaminant uptake go
hand in hand, and if there's a thallium problem, it's really a soil
quality issue, not a kale plant issue per se. If you grow your
vegetables in clean, healthy soil, you will not have heavy metals in
your food, by virtue of there not being any in the soil for the plant to
take up.

Kale Breeding Program Promises Greater Variety

There are
many different varieties of kale, providing different colors, textures
and tastes. Cornell University is also working on a program to identify
and breed consumer favorites, based on shape, color, flavor and texture.
As reported by Science Daily:6

"Griffiths and Swegarden are focusing efforts on developing new
kale cultivars, including the evaluation of hybrid combinations. New
cultivars in Griffiths' breeding pipeline will push consumer
expectations for kale, blurring the current color boundaries of greens
and purples and introducing a range of new leaf and plant shapes …

As part of the program, Swegarden has been gathering feedback
from seed producers, growers, supermarket managers and consumers … She
is partnering with Cornell's Sensory Evaluation Center to perform
consumer trials to develop a consumer kale lexicon and establish a trait
hierarchy that can be used to guide the breeding program.

This data will determine which hybrids and breeding lines to
select in the field. Swegarden predicts that in the next few years
consumers will see an even richer diversity of leafy greens available to
them."

Purple kale

Popular Kale Varieties

The oldest variety of kale is curly
kale, which has ruffled leaves, a deep-green color and a bitter, pungent
flavor. More recent varieties are ornamental kale, Russian and dinosaur
kale, the latter of which has blue-green leaves and a more delicate
taste than curly kale.
Ornamental kale, sometimes called salad savoy, was originally used as
a decorative garden plant (it comes in green, white and purple colors),
although it can also be eaten and has a mellow flavor and tender
texture. As a general rule, kale with smaller leaves tends to be more
tender and milder than larger-leaved varieties. While there are many
options, some of the more popular varieties of kale include:7,8,9

Red Russian, a frost-hardy, slug-resistant variety that is sweeter than most other kinds of kale

Vates, a dwarf kale with curly, blue-green leaves that can tolerate both heat and cold

Dinosaur kale

Kale Is an Ideal Cold Temperature Crop

As a general rule,
kale tastes best when grown in cooler temperatures. Warm weather (or
summer crops) produces more woody and bitter-tasting greens. Optimal
soil temperature is in the 60- to 65-degree F range, but you can
direct-seed into your garden as long as the soil temperature is at least
45 F.
To harvest before the worst summer heat has a chance to take its
toll, start seeds indoors approximately six weeks before your last frost
date.10
Transplanting seedlings into your garden can speed up the maturation
process from an average of 55 to 75 days to as little as 30 or 40.
For a fall crop, plant seeds about eight weeks before your first
frost date. Kale is cold tolerant, and if you live in the north, you can
harvest even after a light snowfall. Most can thrive in temperatures as
low as 15 degrees F, giving you the option of cultivating a winter
crop.
Sow seeds at a depth of about one-half inch. Keep moist but avoid
overwatering as this may cause the seeds to rot. Germination typically
takes about 10 days. Thin the plants once they're 3 to 4 inches tall,
leaving only the healthiest-looking ones. Once the seedlings are about 9
inches tall and four leaves have developed, they're ready to be
transplanted into your garden.

General Growing Tips

• In the early spring and fall, plant
your kale in full sun. If you're growing it during the summer, be sure
the plants have partial shade. Use straw or mulch to preserve moisture
and prevent the roots from excess heat. Just beware that kale will not
generally thrive in the summer, and will be far more bitter than a fall
crop grown in a cooler climate. Kale tends to become more attractive to
pests during the summer as well • Kale tends to prefer slightly acidic
soil that is high in nitrogen. Make sure the soil drains well, but keep
moist to avoid stunting the plant's growth. Lack of moisture will also
render the leaves tough and bitter • Dress with compost every six to eight weeks. Growth can be further boosted by adding a seaweed or fish emulsion once a month • Give each kale plant 12 to 24 inches of space to allow sufficient airflow • Kale grows very well planted next to beets, celery, cucumbers, herbs, onions, spinach, chard and potatoes. Avoid placing it next to beans, strawberries or tomatoes

As a member of the cabbage family, kale is prone to rot diseases like
black rot, club rot and wirestem, and while far more disease-resistant
than many other vegetables, common pests include aphids, cabbage
loopers, cabbageworms, cabbage root fly, cabbage whitefly, cutworms,
flea beetles and slugs.
One of the easiest ways to protect young kale from many of these
pests is to use a featherweight row cover. Once you remove the row
covers, check your plants often for signs of pests and disease.

Harvesting, Storage and Cooking Suggestions

Your kale is ready for harvest once the leaves are about the size of
your hand. Harvest by nipping the outer leaves off from the stem. Be
sure to leave the center leaves to ensure continued growth. As a general
rule, you can harvest three or more leaves from each plant every five
days. Remove any yellowing or wilted leaves, as leaving them on the
plant will encourage pests.
Kale has a relatively short life in terms of crispness, so it's best
to use within a few days of harvesting, although the leaves can be
blanched and frozen for long-term storage. Kale chips are another
popular alternative that will lengthen their shelf life. Here's a simple
kale chip recipe:

Wash and spin dry the chopped, de-stemmed kale. It's important that the kale is completely dry before baking

Toss together the kale and coconut oil. Massage together with your hands until every leaf is coated

Sprinkle on salt, nutritional yeast and any seasoning you will be using. Toss again to evenly distribute

On a parchment-lined baking sheet, arrange the kale evenly without crowding or overlapping

Bake in a 300-degree F oven until crisp and dark green, approximately 12 to 15 minutes

Cool completely before eating. This will allow the chips to crisp up

Kale is versatile in that it can be used either raw or cooked, and
makes for a great addition to a wide variety of dishes. Cut smaller,
paler green leaves into fresh garden salad; use the larger, dark greens
for stir-fries or soup. For even more serving suggestions, see my
previous article, "9 Healthy Kale Recipes." You can even eat kale for breakfast. Instead of eating an egg, try this quick and easy breakfast kale stir-fry:

Chop up half a bunch of kale, a quarter of an onion, and stir-fry in
a tablespoon of coconut oil for a few minutes until the leaves are
tender

Add pinch of sea salt or Himalayan salt, a pinch of pepper, a teaspoon of lemon or Ume Plum Vinegar and some dulse flakes